How to calculate bpm of heart signal stored in the form of an array

For testing purposes I took the sine wave and sampled it. Then I sent the samples to MATLAB using a usart. In MATLAB, I created a port using the serial function. I stored the samples in an array. Now I want to find the bpm pf sine wave. I also want to display signal in real time.

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http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer